This proposal was developed in collaboration with NIMH Program staff and approved for submission by Council at its 1/18/01 meeting. The two aims are:(1) To investigate the effectiveness of medications for children and adolescents who have BP-1 (manic or mixed phase) or mania. (2) To pilot a complex, multistrata, adaptive strategy design. Based on the novelty of the design and on the need for a large (and therefore costly) sample size, the applicants were asked to submit a protocol for only the first two years of the five year plan. If the first two years are successfully implemented, funding for the additional three years will be sought. For the sake of clarity, the proposal is written for the entire five years, even though the budget is limited to the first two years. Thus, the research plan provides for examining 540 subjects ages 6.0-14.11 who have DSM BP-1 (manic or mixed phase) or mania. The structure of this collaborative U01 is one coordinating site and six data collection sites. The coordinating site, for data management and analyses and for training is Washington University, St. Louis, PI: Barbara Geller, M.D. The six sites for data collection are: (1) George Washington University, Washington, D.C.., PI: Paramjit Joshi, M.D. (2) Johns Hopkins Medical Instituitions, Baltimore, PI: John walkup, M.D. (3) University of Pittsburgh, Western Psychiatric Institute and Clinic, PI: David Axelson, M.D. (4) University of Texas, Dallas, PI: Graham Emslie, M.D. (5) University of Texas, Galveston, PI: Karen Dineen Wagner, M.D. and (6) Washington University, St. Louis, PI; Joan Luby, M.D.